Detergent compositions



3,053,771 DETERGENT COMPOSITIONS William G. Toland, San Rafael, and Maurice J. Schlatter,

Berkeley, Calif., assignors to California Research Corporation, San Francisco, Calif, a corporation of Delaware N Drawing. Filed May 6, 1960, Ser. No. 27,252

, 6 Claims. (Cl. 25216l) This invention relates to detergent compositions. More particularly, it relates to a detergent composition having good sudsing characteristics and good suds stability.

Alkylbenzene sulfonate detergents have achieved an extraordinary degree of commercial success and acceptance, particularly detergents prepared by the alkylation of benzene with a propylene polymer fraction having an average from 12 to 15 carbon atoms per molecule, sulfonation of the resultant alkylbenzene, and neutralization of the sulfonic acid, as shown, for example in Lewis Patent No. 2,477,383. 'In the production of solid particle-form detergent compositions containing these alkyl-benzene sulfonates as the active detersive component, inorganic builders in amounts which may range from 60 to 90% by Weight of the total composition are commonly added to the neutrali ationJeaction product mixture to form a slurry which is then spray-dried for packaging. The inorganic builders commonly employed include polyphosphates such as sodium tripolyphosphate, tetrasodium pyrophosphate, alkali metal sulfates, sodium silicate, alkali metal carbonates, and the like. Other conventional additives to detergent formulations are commonly employed. These include anticaking agents, optical bleaches, extenders and preventives of soil redeposition (e.g., carboxymethyl cellulose or derivatives of oxidized cellulose), skin emollients and anti-irritants, perfume and coloring matter.

In household use of these detergent compositions, it has been noted that the suds or foam produced when an aqueous solution of the detergent composition is agitate'd is considerably reduced upon addition of small amounts of fat or other oily material to the aqueous solution. The presence of appreciable amounts of such materials cause such a reduction in the suds density and volume that considerable portions of the surface of the aqueous solution are entirely free of suds or foam. The conditions and requirements of household use and the prejudice of the users are such that a detergent solution may be discarded long before its useful detergent capaci ty has been exhausted, or extensive amounts of the detergent composition may be added to the solution in order to provide what is considered to be the appropriate and necessary amount of suds.

It has now been found that the amount, stability and persistence during continuous agitation of the suds produced by agitating aqueous solutions of alkylbenzene sulfonate detergent compositions in the presence of appreciable amounts of fat or oil may be very markedly increased by incorporating in the detergent composition a small amount of a water-soluble salt of an n-alkyl o-carboxybenzyl sulfide having 12 to 18 carbon atoms in the alkyl group. Particularly preferred is the salt of n-tetradecyl o-carboxybenzyl sulfide. These materials can be represented by the formula wherein R is an alkyl group of 12 to 18, preferably 14, carbon atoms, and M is a salt-forming cation, such as the alkali metals sodium and potassium, and the metal magnesium.

As shown more fully below, these materials are good detergent materials of themselves, and, as indicated, have ice the surprising ability to enhance the foam characteristics of alkylaryl sulf onate detergents. In addition, these materials selectively adsorb on certain metals, e.g., silver, and protect them from tarnishing.

In general, the amount of n-alkyl o-carboxybenzyl sulfide salt can be as little as 1% based on finished composition. Since the foam-boosting additive is itself a good detergent having good foam properties, the upper limit is governed by other considerations than its operability, such as availability, economics, and the like. of the above, an advantageous upper limit is about 20%,

and preferably 10%, by weight, based on finished corn-' position.

In particular, it has been found that a detergent composition consisting essentially of from 15 to 40 parts by weight of an alkylbenzene sulfonate having from 12 to 15 carbon atoms in the alkyl group, 60 to 75 parts by' weight of an inorganic builder, and 1 to 20 parts by weight of water-soluble n-alkyl o-carboxybenzyl sulfide salt, such as the alkali metals sodium and potassium, or

magnesium salts, is characterized by its ability to produce a large volume of persistent suds in an aqueous solution in the presence of appreciable amounts of fat or oil.

The method of incorporating the n-alkyl o-carboxybenzyl sulfide salt is not critical. Accordingly, it can be added before or after spray drying. In commercial practice the former is preferable. The additive is nonvolatile and therefore no loss occurs during spray-drying. By contrast, certain presently used foam improvers, such. as lauryl isopropanolamide, are quite volatile, and losses up to 30% can occur during spray-drying.

The active detergent component of the detergent com-- position may contain C -C alkyl sulfates in addition to the described .alkylaryl sulfonate, the amount of alkyl sulfate ranging from about 25% to 100% of the alkylaryl sulfonate. Detergents containing this mixture of active components are greatly improved in foam and suds properties by the salt material of the present invention.

The preparation of the foam additives of the present invention involves a simple addition reaction of the appropriate l-olefin to o-mercaptobenzoic acid. Taking the preparation of n-tetradecyl o-carboxybenzyl sulfide as typical, a detailed procedure for the preparation of the additive is as follows: o-Mercaptom'ethylbenzoic acid (58.2 g., 0.35 mol) and 103 g. (0.525 mol) of redistilled l-tetradecene are dissolved in absolute ethanol to make a 1-liter solution. Air at 1 mlper minute is bubbled through the solution maintained at 25 C. Conversion of SH groups is followed by iodine titration, and the time of reaction continued accordingly. A white, crys talline precipitate begins to separate after 8 to 10 hours. After termination of the reaction, the precipitate is filtered off, washed with alcohol, and air dried. Further purification of the product may be had by recrystalliza tion from methanol. In order to obtain the salt, e.g., sodium salt of the n-tetradecyl o-carboxybenzy-l sulfide, the compound is dissolved in alcohol, neutralized with an aqueous or alcoholic solution of sodium hydroxide or other base, and then evaporated to dryness to give the salt.

For the purpose of determining the foam characteristics of the detergent composition of the present invention, the bowl or tub of the Washing machine (Dexter twin tub) is filled with wash solution, and charged with a standard load of polyethylene sheeting and 30 cc. of 10% solution of oleic acid in isopropanol. The machine is closed with a plastic cover, and provided with a measuring device to help determine foam height. The machine is run for a total period of 20 minutes at a temperature of about In vieW' 120 F. Readings of foam height, in inches, are made at intervals of 2, 5, 10, 15 minutes and at the end of the 20-minute wash period. Foam height is the average of these readings. Wash solutions are prepared in water of varying hardness, expressed in parts per million of a mixture of calcium carbonate and /3 magnesium carbonate.

To illustrate the practice of the invention, a detergent composition was prepared by alkylating benzene with a fraction of propylene polymer boiling from 360 to 480 F. and consisting essentially of a mixture of propylene tetramers and propylene pentamers. A resultant alkylbenzene is sulfonated with fuming sulfuric acid. The sulfonic acid is neutralized with sodium hydroxide, after which sodium tripolyphosphate, sodium silicate and sodium carboxymethyl cellulose are added to form a slurry which is spray-dried to produce a detergent composition containing 20% by weight sodium alkyl benzene sulfonate, 50% by weight tripolyphosphate, 5% by weight sodium silicate, and 25% by weight sodium sulfate.

A water solution of this detergent composition is prepared having a concentration of 0.2% by weight and to which is added the oleic acid. The water is a synthetic hard water containing 50 parts per million of hardness as defined previously.

When the above formulation is modified by replacing part of the alkylbenzene sulfonate with the additives of the present invention, foam improving effects are notable, as shown in Table I.

TABLE I Foam Boosting Action of n-Alkyl o-Carboxybenzyl Sulfide Salt phate exhibits good foaming properties in the presence of oleic acid.

The n-alkyl o carboxybenzyl sulfide salt of the present invention by itself is shown to have good foam properties (Table II), and, as indicated above, to have good detergent characteristics when admixed with 60 to 90% by weight based on finished composition of the commonly employed detergent builders mentioned above. In this connection, a number of experiments were run employing the Terg-O-Tometer test, and Foster D. Snell soiled cotton, as described in Detergency Evaluation and Testing, by J. C. Harris, Interscience Manual 4, Interscience Publishers, Inc., New York.

In the tabulated experiments in Table IV, the formulations were as follows: 20% active detergent material, that is, the sodium salt of the indicated l-olefin adduct of o-mercaptomethylbenzoic acid, namely, the n-C C alkyl o-carboxybenzyl sulfide salt; 50% sodium tripolyphosphate; 5% N silicate; 1% carboxymethyl cellulose; and 24% sodium sulfate.

TABLE 'IV Detergency of n-Alkyl o-Carboxybenzyl Sulfides, Sodium Salts Hardness, p.p.m. 5O 50 50 300 300 300 Concentration of Formulation,

Percent 0.1 0.2 0.3 0.1 0.2 0.3

Percent Soil Removal 59 15 17 53 55 20 20 50 57 17 16 Ola Adduct 59 Efiects of varying the amount of additive relative to alkylaryl sulfonate in the same heavy duty formula are shown in Table II.

TABLE II Efiect of Percentages of Additive in Formulations Additive None 014 Adduct Percent 0.5 1 2 3 1O Alkylaryl Sultanate. 20 19.5 19 18 17 15 10 5 0 Foam, in 1.9 2.5 4.1 4.1 4.3 3.9 3.8 4.0 3.9

The effect of varying the water hardness is shown in Table III.

As a further illustration of the invention, a detergent composition prepared as above and containing by weight magnesium alkylbenzene sulfonate, 5% by weight magnesium sulfate, 5% by weight n-tetradecyl o-carboxybenzyl sulfide, and the remainder sodium tripolyphos- 1 Hardness, determined as hereinabove described.

We claim:

1. A detergent composition consisting essentially by weight of 15 to 40 parts of water-soluble alkylbenzene sulfonate detergent having from 12 to 15 carbon atoms in the alkyl group, 60 to parts of water-soluble inorganic detergent builders and, as a foam improving agent, 1 to 20 parts of a water-soluble n-alkyl o-carboxybenzyl sulfide salt having 12 to 18 carbon atoms in the alkyl group.

2. The composition according to claim 1 wherein the foam-improving agent is n-tetradecyl o-carboxybenzyl sulfide.

3. The composition according to claim 1 wherein sulfonate detergent is derived from a salt-forming metal selected from the group consisting of sodium and magnesium.

4. The composition according to claim 3 wherein the foam-improving agent is n-tetradecyl o-carboxybenzyl sulfide salt.

5. A detergent composition consisting essentially by weight of 10 to 40 percent of a water-soluble n-alkyl o-carboxybenzyl sulfide salt having 12 to 18 carbon atoms in the alkyl group and 60 to percent of water-soluble inorganic salt detergent builders.

6. The composition according to claim 5 wherein the n-alkyl o-carboxybenzyl sulfide salt is derived from n-tetradecyl o-carboxybenzyl sulfide.

References Cited in the file of this patent UNITED STATES PATENTS 2,477,383 Lewis July 26, 1949 2,862,956 Gundel et al Dec. 2, 1958 OTHER REFERENCES Schwartz et a1: Surface Active Agents, 1949, Interscience Pub. Inc., p. 41. 

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY BY WEIGHT OF 15 TO 40 PARTS OF WATER-SOLUBLE ALKYLBENZENE SULFONATE DETERGENT HAVING FROM 12 TO 15 CARBON ATOMS IN THE ALKYL GROUP, 60 TO 75 PARTS OF WATER-SOLUBLE INORGANIC DETERGENT BUILDERS AND, AS A FOAM IMPROVING AGENT, 1 TO 20 PARTS OF A WATER-SOLUBLE N-ALKYL O-CARBOXYBENZYL SULFIDE SALT HAVING 12 TO 18 CARBON ATOMS IN THE ALKYL GROUP. 